A Noise Cross-Extraction and Iterative Spectral Subtraction Method for Suppressing Additive Noise in Fiber Bragg Grating Sensing System

Additive noise suppression is a critical challenge for achieving high-accuracy demodulation in fiber Bragg grating (FBG) sensing systems, particularly under low signal-to-noise ratio (SNR) conditions. This paper proposes a noise cross-extraction and iterative spectral subtraction method for suppressing additive noise in FBG sensing systems. The method involves the synchronous acquisition of spectral signals from the identical FBG sensor using a dual-channel photoelectric detection system. By exploiting the correlation between the signals, additive noise is cross-extracted. Following that, an iterative spectral subtraction method is employed to suppress the extracted noise. Simulation results demonstrate that even at an SNR as low as 5 dB, the accuracy improves by 94.64% after 10 iterations. Further experiments confirm the effectiveness of the proposed method, achieving an accuracy improvement of 98.08% after 3 iterations. Thus, the proposed method provides an effective solution for high-accuracy demodulation of FBG sensing systems.